#include <iostream>
#include <iomanip>

using namespace std;

int main_0022(void)
{
    int num = 0;
    cin >> num;

    double ages = 0;
    int age = 0;

    for (int i = 0; i < num; ++i) {
        cin >> age;
        ages += age;
    }

    cout << fixed << setprecision(2) << ages / num;
    return 0;
}
